For most entrepreneurs, the predominent source of income is from the sale of the main products and/or services offered. The term main product and/or services is used very broadly in this section. A pet shop owner derives the bulk of the income from the sale of pets, pet food, accessories, and consumables. Thus the main products in this case are pets, pet food, accessories and consumables.
For a firm providing home DIY service, the predominant source of income is the actual service rendered in term of hours worked. In addition, the firm usually gets to sell, at a profit, products which are used for the DIY service. These products are considered main products as they are fundamental to the service being provided.
It is easy to assume that all firms must have income from the sale of main products and/or services. However this is not correct. Although it seems baffling, there are many firms which do not have income from the sale of main products and/or services. They have other sources of income which are covered in subsequent pages.